KR20180044252A - Metal nanowire and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a manufacturing method of a metal nanowire, which uses a carbon nanostructure of which a double surface is functionalized with an amine group and a carboxylic acid as a template to improve economic feasibility and productivity.

Description

TECHNICAL FIELD [0001] The present invention relates to a metal nanowire and a method of manufacturing the same,

The present invention relates to a method for producing metal nanowires which can improve economic efficiency and productivity by using a carbon nanostructure having a double surface functionalized with an amine group and a carboxylic acid as a template.

The metal nanowire, which is a structure composed of a single crystal of metal, has high chemical stability, excellent electrical conductivity and thermal conductivity, and thus has a very high value in various fields requiring electrical, optical, mechanical and thermal characteristics.

The metal nanowires are required to have various physical properties such as uniform shape, good surface condition, and high aspect ratio. For this purpose, a number of process steps are required for manufacturing, and there is a problem such as a long time come.

As metal nanowires, mainly silver (Ag) nanowires are used. This is because silver salts have been limitedly selected for the reason of the complicated manufacturing process which requires several steps among various metal precursors, and silver nitrate is generally limited to silver nitrate (AgNO ₃ ). Except for this, satisfactory physical properties and yields are not obtained, and the burden is high due to an increase in manufacturing cost. Copper is used as another metal because it has a high degree of oxidation. However, there is a problem that a post-treatment process for removing the oxide film on the surface of the nanowire should be additionally performed.

Metallic nanowires are synthesized mainly on the basis of crystal - selective chemical reduction in polyol solution. However, the production cost is high and the reaction in the synthesis process is very sensitive, so that there are restrictions in practical application.

Therefore, research and development of a manufacturing method of metal nanowires that are easy to process without being limited to crystal-selective chemical reduction method based on a low-cost metal material that can reduce the manufacturing cost and simplify the process It is necessary.

1) Korean Patent No. 10-1465467 (2014.11.20.)

DISCLOSURE Technical Problem In order to solve the above problems, it is an object of the present invention to provide a method of manufacturing metal nanowires that can remarkably reduce manufacturing costs and simplify a process and improve productivity.

Another object of the present invention is to provide a metal wire capable of realizing a synergistic effect of electrical and optical characteristics such as high conductivity and high light transmittance by using carbon nanotubes as a template.

In order to achieve the above object,

(a) reacting a carbon nanotube-containing solution containing a carbon nanotube, an amine compound and an acid anhydride to produce an aminated carbon nanotube,

(b) sonicating the aqueous dispersion obtained by mixing the aminated carbon nanotube, the water-soluble polymer and water, and

(c) mixing the ultrasound-treated aminated carbon nanotube as a template, the ultrasonic treated aminated carbon nanotube, the metal precursor and the solvent in an inert atmosphere, adding a reducing agent, and reacting

The present invention also provides a method of manufacturing a metal nanowire using the carbon nanotube template.

In the method for manufacturing a metal nanowire using a carbon nanotube template according to an embodiment of the present invention, the acid anhydride in step (a) may be a polycyclic aromatic cyclic acid anhydride. At this time, the polycyclic aromatic cyclic acid anhydride may be any one selected from pyrene-based cyclic acid anhydride, chrysene-based cyclic acid anhydride, perylene-based cyclic acid anhydride, triphenylene-based cyclic acid anhydride and coronene- Or a mixture of two or more.

In the method of manufacturing a metal nanowire using a carbon nanotube template according to an embodiment of the present invention, the water soluble polymer in step (b) may be any one selected from polyacrylic acid, polymethacrylic acid, carboxymethylcellulose, It may be a mixture of two or more. The water-soluble polymer may have a weight average molecular weight of 1,000 to 20,000 g / mol.

In the method of manufacturing a metal nanowire using the carbon nanotube template according to an embodiment of the present invention, the carbon nanotube may be a multi-walled carbon nanotube.

In the method of manufacturing a metal nanowire using a carbon nanotube template according to an embodiment of the present invention, the step (a) may further include washing and drying the nanoparticles after reacting the solution, followed by centrifugation.

In the method of manufacturing a metal nanowire using a carbon nanotube template according to an embodiment of the present invention, the step (b) may further include washing and drying after reacting the aqueous dispersion and centrifuging.

In the method of manufacturing a metal nanowire using a carbon nanotube template according to an embodiment of the present invention, mixing in an inert atmosphere in step (c) may be performed at 110 to 150 ° C.

In the method of manufacturing a metal nanowire using a carbon nanotube template according to an embodiment of the present invention, in the step (c), the metal precursor may be a C2-C24 linear or branched aliphatic, And may be a carboxylate of a metal derived from an ester compound which is an aliphatic ring or an aromatic carboxylic acid or a derivative thereof.

In the method of manufacturing a metal nanowire using a carbon nanotube template according to an embodiment of the present invention, the reducing agent may be selected from the group consisting of a hydrazine system, a hydride system, a sodium phosphate system and an ascorbic acid in the step (c) Or a mixture of two or more thereof.

The manufacturing method of the metal nanowire according to the present invention can remarkably reduce the manufacturing cost and simplify the manufacturing process, thereby remarkably improving the productivity, which is economically advantageous.

1 is a scanning electron micrograph (SEM: 100,000 times) of a metal nanowire fabricated on a synthesized carbon nanotube template according to an embodiment of the present invention.
2 is a scanning electron microscope (SEM: 30,000 times) of metal nanowires fabricated on a synthesized carbon nanotube template according to an embodiment of the present invention.
FIG. 3 is an X-ray diffraction pattern (XRD) of a metal nanowire fabricated on a synthesized carbon nanotube template according to an embodiment of the present invention.

Hereinafter, a method of manufacturing a metal nanowire using the carbon nanotube template of the present invention will be described in detail with reference to preferred embodiments. However, this is not intended to limit the scope of protection defined by the claims. In addition, technical terms and scientific terms used in the description of the present invention have the meanings as commonly understood by those of ordinary skill in the art to which the present invention belongs, unless otherwise defined.

The inventors of the present invention have found that by including a carbon nanostructure having a double functionalized surface with an amine group and a carboxylic acid as a template and ultrasonically treating the aqueous dispersion containing the double-surface functionalized carbon nanostructure and the water-soluble polymer, It is possible to provide a method of manufacturing a metal nanowire using a carbon nanotube template capable of simplifying a process and drastically reducing cost by a reduction reaction using a compound, and completed the present invention.

A method of manufacturing a metal nanowire using the carbon nanotube template according to the present invention includes:

(a) reacting a carbon nanotube-containing solution containing a carbon nanotube, an amine compound and an acid anhydride to produce an aminated carbon nanotube,

(b) sonicating the aqueous dispersion obtained by mixing the aminated carbon nanotube, the water-soluble polymer and water, and

(c) mixing the ultrasound-treated aminated carbon nanotubes with the ultrasound-treated aminated carbon nanotubes, the metal precursor, and the solvent in an inert atmosphere, and then adding a reducing agent and reacting.

In the present invention, step (a) is a step for preparing aminated carbon nanotubes. In the present invention, the aminated carbon nanotubes refer to carbon nanotubes whose surface is functionalized with an amine group.

The aminated carbon nanotubes are prepared by reacting carbon nanotube-containing solutions containing carbon nanotubes, amine compounds, and acid anhydrides.

The carbon nanotubes of the present invention are not particularly limited, but are preferably single-walled carbon nanotubes (SWCNTs), double-walled carbon nanotubes (DWCNTs) And multi-walled carbon nanotubes (MWCNT). More preferably, the multi-walled carbon nanotube is thicker in wall thickness, structurally more stable, and has a long length, so that it is preferable to synthesize the composite material according to the present invention and is economical in terms of cost reduction of materials. At this time, the carbon nanotubes can be used without being limited to the length, diameter, and density.

The amine compound is used for introducing an amine group and is not limited as long as it reacts with an acid anhydride to facilitate the introduction of an amine group. It is more preferable to use a diamine compound containing two amine groups. The aromatic diamine may be, for example, ρ-phenylenediamine, and the aliphatic diamine may be an alkylenediamine such as ethylenediamine, propylenediamine, butylenediamine or the like, or an ρ- Cycloalkanediamine such as cyclohexanediamine, and the like.

In the present invention, the acid anhydride is not particularly limited, but amine groups can be more easily introduced into the surface of the carbon nanotubes by using polycyclic aromatic cyclic acid anhydrides. The polycyclic aromatic cyclic acid anhydride is capable of easily adsorbing a polycyclic aromatic compound on the surface of the carbon nanotube by a π-π interaction with the carbon nanotube, and is capable of preventing the occurrence of defects in the carbon nanotube, It is possible to realize a synergistic effect that can be modified.

The polycyclic aromatic cyclic acid anhydride may be one containing a plurality of benzene rings and a cyclic acid anhydride group for introducing an amine group, although not limited thereto. Preferably, it may contain 4 or more benzene rings for improving the adsorption ability between the carbon nanotubes and the polycyclic aromatic cyclic acid anhydride, more preferably 4 to 10 benzene rings. Examples of the polycyclic aromatic cyclic acid anhydride include pyrene cyclic acid anhydride, chrysene cyclic acid anhydride, perylene cyclic acid anhydride, triphenylene cyclic acid anhydride, And a coronene cyclic acid anhydride. [0033] The term " coronene cyclic acid anhydride "

The carbon nanotube-containing solution can be mixed with carbon nanotubes, amine compounds, and anhydrides together with methylene chloride. At this time, methylene chloride can improve the solubility of organic molecules and the dispersibility of carbon nanotubes. It is not necessarily limited to methylene chloride, and any solvent that can be used instead of methylene chloride can be used without limitation.

The mixed solution is subjected to sonication. Ultrasonic processing can ultrasonically function the surface of carbon nanotubes to amine groups through dispersion of reactants.

The carbon nanotube-containing solution is not particularly limited, but may be composed of 0.1 to 5 wt% of carbon nanotubes, 1 to 10 wt% of amine compound, and 0.1 to 5 wt% of acid anhydride. When the above range is satisfied, the carbon nanotubes can be smoothly reacted without causing the aggregation or precipitation of the carbon nanotubes.

In one embodiment of preparing aminated carbon nanotubes, the carbon nanotube-containing solution is mixed with methylene chloride, followed by ultrasonic treatment to prepare a dispersion solution, followed by further stirring. Thereafter, a precipitate is obtained through centrifugation, re-dispersed again with water, and then centrifuged again to obtain a precipitate. This precipitate is re-dispersed using methanol, which is centrifuged again to obtain a precipitate. The centrifugal separation step is not limited, but it can be repeatedly carried out, preferably about 10,000 rpm for about 15 minutes, twice. The resulting precipitate is dried in a vacuum oven at room temperature for 24 hours.

In the present invention, step (b) is a step of ultrasonically mixing an aqueous dispersion using a water-soluble polymer. The aqueous dispersion mixed with the water-soluble polymer and water is prepared by using the aminated carbon nanotubes prepared in the step (a), ultrasonicated and centrifuged to obtain a precipitate. At this time, the ultrasonic treated aqueous dispersion is mixed with the C ₁ -C ₄ alcohol compound. The volume ratio of the ethanol and the aqueous dispersion is not particularly limited, but is preferably 1.5: 1 to 1: 1.5, Is closer to 1: 1. Preferably, the precipitate is centrifuged twice using ethanol as a solvent to obtain a precipitate.

At this time, the water-soluble polymer is used for aggregation or growth of metal particles and is not particularly limited, but may be used without limitation as long as it includes a carboxylic acid. Specifically, it may be any one or a mixture of two or more selected from polyacrylic acid, polymethacrylic acid, carboxymethylcellulose and salts thereof. Preferably, the water-soluble polymer may be one having a dissociation group in the polymer chain to dissolve in water and dissociate. Dissociation groups present in the polymer chain is carboxy carbonate group (-COO-), sulfonate group (-SO ₃ -), sulfate group (-OSO ₃ -), phosphate groups (-OPO ₃ -), and phosphonate group (-PO ₃ -), and the like, but not always limited thereto. In addition, the cation which forms a salt in combination with the dissociation group may include a metal cation such as sodium, an ammonium cation, an amine cation, and the like.

A more preferred water-soluble polymer in the present invention may be sodium polyacrylate.

The water-soluble polymer is not particularly limited, but preferably has a weight average molecular weight (Mw) of 1,000 to 20,000 g / mol. When the above range is satisfied, it is possible to smoothly produce metal nanowires and realize excellent performance in terms of physical properties, conductivity, and mechanical properties of the carbon nanotube-metal nanowires to be produced.

In the present invention, the aqueous dispersion is not particularly limited, but it is more preferable to mix 0.05 to 0.3% by weight of aminated carbon nanotubes, 0.01 to 0.1% by weight of water-soluble polymer and 99.94 to 99.6% by weight of water. If the amount of the water-soluble polymer is insufficient relative to the aminated carbon nanotube, the functionalization with the carboxylic acid is not sufficiently performed. If the amount of the aminated carbon nanotubes in the aqueous dispersion exceeds the above range, the dispersibility becomes poor and the uniform functionalization of the carboxylic acid is difficult .

It is further preferable that the pH of the aqueous dispersion is 5 or more. This is to improve the yield of metal nanowire formation during the reduction reaction of the metal from the metal precursor, and a base may be added to adjust the pH. The base in the solution may be NaOH, KOH, triethylamine or the like.

In the present invention, step (c) is a step of preparing a metal nanowire by reducing a metal from a metal precursor on a carbon nanotube template.

The aminated carbon nanotubes ultrasonicated with the water-soluble polymer are mixed with a metal precursor and a solvent. Mixing is carried out in an inert atmosphere, and when sufficient mixing is achieved, a reducing agent is added and allowed to react. At this time, the mixing is preferably performed at 110 to 150 ° C. The reaction time is not particularly limited, but is preferably 1 to 30 minutes and 3 to 10 minutes. After the reaction is complete, the reaction is obtained as a precipitate precipitated using centrifugation. At this time, the solvent used in the centrifugation is not particularly limited, but toluene can be preferably used.

In the present invention, the metal precursor may be selected from the group consisting of an organic acid salt, an inorganic acid salt or a halide of any metal selected from the group consisting of copper, silver, gold, nickel, tin, aluminum and alloys thereof. May be a carboxylate of a metal derived from an ester compound of C ₂ to C ₂₄ linear or branched aliphatic, aliphatic ring or aromatic carboxylic acid or derivative thereof containing at least one carboxyl group . In one embodiment, the metal precursor is selected from the group consisting of metal acetate, metal benzoate, metal lactate, metal citrate, metal cyclohexane butyrate, metal ethyl hexanoate, metal trifluoroacetate, metal heptafluorobutyrate, have. Preferably, metal acetate is used.

A more preferred metal precursor in the present invention may be copper acetate. Copper has oxidation problems and is more susceptible to oxidation problems due to its surface area per volume when forming nanostructures. However, copper oxide is characterized in that it is easily reduced due to its low potential of reduction, unlike silver or gold. In the present invention, by using copper The metal nanowires can be manufactured at a low cost as compared with silver, so that an economical effect can be realized.

The metal precursor may be a solution in which an acid allowing anion substitution is dissolved. For example, when metal acetate is used, nitric acid, which is a stronger acid than COOCH ₃ , the counterpart of the anion (COOCH ₃ ^- ) contained in the precursor, can be used. That is, even when a metal precursor having a low solubility in a solvent is used by substituting the anion of the metal precursor with the strong base of the strong acid, the reduction reaction of the metal becomes possible.

In the present invention, the reducing agent is used for reducing a metal to a metal form, and may be any one or a mixture of two or more selected from the group consisting of a hydrazine series, a hydride series, a sodium phosphate series and an ascorbic acid. Preferably hydrazine-based reducing agents including hydrazine, hydrazine anhydride, hydrazine hydrochloride, hydrazine sulfate, hydrazine hydrate and phenylhydrazine. In addition to the hydrazine-based reducing agent, a boride compound including a hydride-based compound, more preferably tetrabutylammonium borohydride, tetramethylammonium borohydride, tetraethylammonium borohydride, and sodium borohydride, A hydride-based reducing agent may be used. In addition, one or more of sodium phosphate-based reducing agent and ascorbic acid can be selected and used, and the present invention is not limited thereto.

Hereinafter, the present invention will be described in detail with reference to the following examples. However, the present invention is not limited to the following examples.

The physical properties of the present invention were measured as follows.

(Example 1)

Multi-walled carbon nanotubes (MWCNT) [Applied Carbon Nano Technology Co. Ltd., A-Tube-AM97, carbon content of 97% by weight], 0.35 g of perylene-3,4,9,10-tetracarboxylic dianhydride (PTD), 0.1 g of ethylene diamine ) And 70 mL of trimethylamine are mixed with 350 mL of methylene chloride, and sonicated for 1 hour to prepare a dispersion solution. After further stirring for 24 hours, centrifuge (10,000 rpm, 15 minutes) to obtain a precipitate. The precipitate is re-dispersed using water as a solvent, and then centrifuged again to obtain a precipitate. The process of re-dispersing the precipitate using methanol as a solvent and then centrifuging to obtain a precipitate is repeated twice. The resulting precipitate is dried in a vacuum oven (25 DEG C) for 24 hours to obtain amine-treated multi-walled carbon nanotubes.

0.006 g of 35 wt% polyacrylic acid sodium salt (Mw: 15,000 g / mol) was added to 13.313 g of distilled water, 0.02 g of amine-treated multi-walled carbon nanotube (MWCNT) Mixing is carried out to make a dispersion solution. The dispersion solution and ethanol are mixed at a ratio of 1: 1 by volume and centrifuged to obtain a precipitate. For washing, the precipitate was redispersed using ethanol as a solvent and centrifuged to obtain a precipitate twice. The resulting precipitate was dried in a vacuum oven (25 ° C) for 24 hours and then post-treated with polyacrylic acid Thereby obtaining an amine-treated multi-walled carbon nanotube.

58.902 g of octylamine, 0.02 g of amine-treated multi-walled carbon nanotubes post-treated with polyacrylic acid, 2.511 g of oleic acid and 1.038 g of copper acetate were mixed in an inert gas atmosphere . After raising the temperature of the reactor to 130 ° C, phenylhydrazine was added and reacted for 5 minutes. Then, the reaction product was centrifuged and extracted with toluene to prepare synthesized copper nanowires.

1 and 2 are SEM micrographs (SEM, 100,000 / 30,000 times) of the metal nanowires formed on the carbon nanotube template synthesized according to Example 1, showing a diameter of about 50 nm and a length of 20 m It can be confirmed that the metal nanowires formed on the carbon nanotube template are formed.

FIG. 3 shows the X-ray diffraction pattern (XRD) of the metal nanowires formed on the carbon nanotube template. It can be confirmed that the copper nanowires were uniformly coated on the surface of the double functionalized carbon nanotubes, It was confirmed that a thin oxide film exists on the surface of the copper metal layer due to the presence of a slight amount of copper oxide.

(Example 2)

(CBDA), 4,4 '- (hexafluoroisopropylidene) diphthalic anhydride (6FDA), 4,4' - tetracarboxylic dianhydride (CBDA) instead of using polycyclic aromatic cyclic acid anhydrides as acid anhydrides, -oxydiphthalic dianhydride (ODA) was used as the starting material. As a result, it can be confirmed that metal nanowires are formed on the carbon nanotube template.

(Example 3)

The procedure of Example 1 was repeated except that sodium carboxymethylcellulose (AkuAlik DL-40, Nihon Shokubai Co., Ltd.) was used instead of polyacrylic acid sodium salt. As a result, it can be confirmed that metal nanowires are formed on the carbon nanotube template.

(Comparative Example 1)

58.902 g of octylamine, 0.02 g of multi-walled carbon nanotubes, 2.511 g of oleic acid and 1.038 g of copper acetate were mixed in an inert gas atmosphere. After raising the temperature to 130 ° C, phenylhydrazine is injected and reacted for 5 minutes. The synthesized metal nanowires were extracted through centrifugation and washed twice with toluene as a solvent. As a result, no metal nanowires were formed on the carbon nanotube template.

(Comparative Example 2)

1.4 g of multi-walled carbon nanotubes (MWCNT), 0.35 g of perylene-3,4,9,10-tetracarboxylic dianhydride (PTD), 0.1 g of ethylene diamine ) And 70 mL of trimethylamine are mixed with 350 mL of methylene chloride, and sonicated for 1 hour to prepare a dispersion solution. After further stirring for 24 hours, centrifuge (10,000 rpm, 15 minutes) to obtain a precipitate. The precipitate is re-dispersed using water as a solvent, and then centrifuged again to obtain a precipitate. The process of re-dispersing the precipitate using methanol as a solvent and then centrifuging to obtain a precipitate is repeated twice. The resulting precipitate is dried in a vacuum oven (25 DEG C) for 24 hours to obtain amine-treated multi-walled carbon nanotubes.

58.902 g of octylamine, 0.02 g of amine-treated multi-walled carbon nanotubes, 2.511 g of oleic acid and 1.038 g of copper acetate were mixed in an inert gas atmosphere. After raising the temperature to 130 ° C, phenylhydrazine is injected and reacted for 5 minutes. The synthesized metal nanowires were extracted through centrifugation and washed twice with toluene as a solvent. As a result, no metal nanowires were formed on the carbon nanotube template.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Various modifications and variations are possible in light of the above teachings.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

Claims (11)

(a) reacting a carbon nanotube-containing solution containing a carbon nanotube, an amine compound and an acid anhydride to produce an aminated carbon nanotube,
(b) sonicating the aqueous dispersion obtained by mixing the aminated carbon nanotube, the water-soluble polymer and water, and
(c) mixing the ultrasound-treated aminated carbon nanotube as a template, the ultrasonic treated aminated carbon nanotube, the metal precursor and the solvent in an inert atmosphere, adding a reducing agent, and reacting
Wherein the carbon nanotube template is a metal nanowire.
The method according to claim 1,
Wherein the acid anhydride in step (a) is a polycyclic aromatic cyclic acid anhydride.
3. The method of claim 2,
The polycyclic aromatic cyclic acid anhydride may be any one or two selected from pyrene-based cyclic acid anhydride, chrysene-based cyclic acid anhydride, perylene-based cyclic acid anhydride, triphenylene-based cyclic acid anhydride and coronene cyclic acid anhydride. Wherein the metal nanowire is a mixture of carbon nanotubes.
The method according to claim 1,
Wherein the water-soluble polymer in step (b) is one or a mixture of two or more selected from the group consisting of polyacrylic acid, polymethacrylic acid, carboxymethyl cellulose, and salts thereof.
5. The method of claim 4,
Wherein the water-soluble polymer has a weight average molecular weight of 1,000 to 20,000 g / mol.
The method according to claim 1,
Wherein the carbon nanotubes are multi-wall carbon nanotubes.
The method according to claim 1,
Wherein the step (a) further comprises reacting the solution, followed by centrifugation, followed by drying, to obtain a metal nanowire using the carbon nanotube template.
The method according to claim 1,
Wherein the step (b) further comprises reacting the aqueous dispersion, followed by centrifugation, and then drying the carbon nanotube template.
The method according to claim 1,
Wherein the mixing is performed at 110 to 150 < 0 > C in an inert atmosphere in step (c).
The method according to claim 1,
In the step (c), the metal precursor may be a carboxylate of a metal derived from an ester compound which is a linear or branched C2-C24 aliphatic, aliphatic ring or aromatic carboxylic acid or derivative thereof containing at least one carboxyl group Wherein the carbon nanotube template is a carbon nanotube template.
The method according to claim 1,
Wherein the reducing agent is at least one selected from the group consisting of hydrazine, hydride, sodium phosphate, and ascorbic acid, and wherein the reducing agent is a mixture of two or more selected from the group consisting of hydrazine, hydride, sodium phosphate and ascorbic acid.

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